Stacked Mounting Structure and Method of Manufacturing Stacked Mounting Structure

ABSTRACT

There is provided a stacked mounting structure in which, it is possible to realize a narrowing of pitch and to secure a height which enables to mount components to be mounted, and a method of manufacturing stacked mounting structure. 
     The stacked mounting structure includes a plurality of members provided with a mounting area which is necessary for installing and operating components to be mounted on at least one principal surface, and an area for connections for signal transfer for operating the components to be mounted, and an electroconductive member which is disposed on the area for connections between the mutually facing members, and a cross section of the electroconductive member is same as or smaller than the area for connections, and an end portion of the electroconductive member is extended from a principal surface of one member up to a principal surface of the other member, and a height of the electroconductive member regulates a distance of the mounting area.

TECHNICAL FIELD

The present invention relates to a stacked mounting structure and amethod of manufacturing stacked mounting structure.

BACKGROUND ART

As a substrate connecting member which connects electronic circuitboards which are stacked, a substrate connecting member described inPatent Literature 1 (Japanese Patent Application Laid-open PublicationNo. 2001-144399) is available. This substrate connecting member is amember which covers a core body made of a stiff conductor by an elasticbody, and which covers the surrounding of the elastic body by anelectroconductive material. By structuring the substrate connectingmember in such manner, there is an effect that heating is not necessaryto separate the electronic circuit board at the time of a repairing job.

Moreover; as another conventional example, for realizing a small and ahighly dense substrate in which electronic components are built-in, astructure in which, electrodes of the electronic components are exposedby carrying out a process of grinding and perforating on a resin afterthe electronic components are fixed by resin in a through hole in acircuit-board main body, and further, a circuit layer is formed on afront and a rear surface of the circuit-board main body, has beenproposed.

Patent Literature 1: Japanese Patent Application Laid-open PublicationNo. 2001-144399

DISCLOSURE OF INVENTION Technical Problem

However, although narrowing of pitch was possible in the substrateconnecting member described in Patent Literature 1, there were followingproblems. In other words, (1) stacked electronic circuit boards weresupposed to be attached and detached mutually, (2) assembling andposition adjustment in a recess in a case of forming a plurality ofconnecting members have been difficult, (3) stacking of a multiplenumber of electronic circuit boards has not been taken intoconsideration, and (4) at least two members namely the core body and theelastic body being necessary, small sizing had been difficult.

Moreover, in the another conventional example mentioned above, theelectronic components which can be built-in in a substrate thicknesswere restricted to components having a height smaller than the substratethickness, and also, the circuit layer on the front and rear surface ofthe board main body had to be connected via the electronic components,due to which there had been substantial restrictions in designing of thecircuit layer. In a case of connecting the circuit layer on the frontand rear surface of the board main body upon bypassing the electroniccomponents, the connections can be made via a through hole, but it isnecessary to provide an electrode pad (land electrode) larger than athrough-hole diameter, and since the narrowing of pitch of the boardconnecting portion was difficult, there had been limitations on makingsmall an area of a principal surface of the substrate.

The present invention has been made in view of the abovementionedcircumstances, and an object of the present invention is to provide astacked mounting structure in which, it is possible to realize thenarrowing of pitch and to secure a height which enables to mountcomponents, and a method of manufacturing stacked mounting structure.Moreover, another object of the present invention is to provide astacked mounting structure in which, a degree of freedom of wiring ofthe substrate is high, and the narrowing of pitch of the substrateconnecting portions is possible, and accordingly, the area of theprincipal surface of the substrate is small.

Technical Solution

To solve the abovementioned problems and to achieve the object, thestacked mounting structure of the present invention includes

a plurality of members provided with a mounting area which is necessaryfor installing an operating components to be mounted on at least oneprincipal surface, and an area for connections for signal transfer foroperating the components to be mounted, and

an electroconductive member which is disposed on the area forconnections between the mutually facing members, and

a cross-section of the electroconductive member is same as or smallerthan the area for connections, and an end portion of theelectroconductive member is extended from a principal surface of onemember up to a principal surface of the other member, and a height ofthe electroconductive member regulates a distance of the mounting area.

In the stacked mounting structure of the present invention, it ispreferable that a reinforcing member is installed around theelectroconductive member.

In the stacked mounting structure of the present invention, it isdesirable that the components to be mounted are mounted on the mountingarea, and a distance of the mounting area between the plurality ofmembers is more than a height of the components to be mounted.

In the stacked mounting structure of the present invention, it ispreferable that the reinforcing member is filled in the mounting areabetween the mutually facing members.

In the stacked mounting structure of the present invention, it ispreferable that the electroconductive member is rod-shaped.

In the stacked mounting structure of the present invention, it isdesirable that the electroconductive member, in a state of one endportion thereof joined, the other end portion is mounted on the member,and is formed by removing the portion joined after the other end portionis mounted on the member.

In the stacked mounting structure of the present invention, it ispreferable that an electroconductive pattern of which, at least a partis electrically connected to the electroconductive member, is formed atone end portion of the reinforcing member.

Moreover, a method of manufacturing stacked mounting structure includessteps of:

mounting components to be mounted, and mounting an electroconductivemember which is higher than a height of the components to be mounted, ona first member,

a reinforcing step of forming a reinforcing member around theelectroconductive member on the first member by exposing an end portionof the electroconductive member, at an opposite side of the firstmember, and

at the reinforcing step, a surface of the reinforcing member, oppositeto the first member is flattened by grinding, and an end portion of theelectroconductive member is exposed.

In the method of manufacturing stacked mounting structure of the presentinvention, it is desirable that the method of manufacturing stackedmounting structure further includes a joining step of forming one endportion of the electroconductive member, in a state of the plurality ofelectroconductive members joined.

In the method of manufacturing stacked mounting structure of the presentinvention, it is preferable that the method of manufacturing stackedmounting structure includes steps of: forming a metal film on anend-portion surface of the electroconductive member which is exposed,after the reinforcing member is formed by exposing the end portion ofthe electroconductive member, on the opposite side of the first member,and a step of forming a bump on the metal film of the end-portionsurface of the electroconductive member.

In the method of manufacturing stacked mounting structure of the presentinvention, it is preferable that the method of manufacturing stackedmounting structure includes a separating step after aninsulating-material forming step, and that the first member has a sizeequivalent to a plurality of modules.

According to the stacked mounting structure and the method ofmanufacturing stacked mounting structure of the present invention, thereis shown an effect that it is possible to provide a stacked mountingstructure in which, it is possible to realize a narrowing of pitch andto secure a height, which enables to mount components to be mounted, anda method of manufacturing stacked mounting structure.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is perspective view showing a structure of a stacked mountingstructure according to a first embodiment, by separating into a firstsubstrate and a second substrate.

FIG. 2 is a cross-sectional view showing a structure of the stackedmounting structure according to the first embodiment;

FIG. 3 is a perspective view showing a structure of a stacked mountingstructure according to a second embodiment, by separating into a firstsubstrate and a second substrate;

FIG. 4 is an enlarged perspective view showing a relationship of anelectroconductive member and a reinforcing member according to thesecond embodiment;

FIG. 5 is a perspective view showing a structure of a stacked mountingstructure according to a third embodiment;

FIG. 6 is a flowchart showing a flow of a method of manufacturingstacked mounting structure according to a fourth embodiment;

FIG. 7 is a flowchart showing a flow of a method of manufacturingstacked mounting structure according to a fifth embodiment;

FIG. 8 is a flowchart showing a flow of a method of manufacturingstacked mounting structure according to a sixth embodiment;

FIG. 9 is a diagram of which, a right side is an enlarged perspectiveview showing a structure of a stacked mounting structure correspondingto steps from step S1 to step S6 in FIG. 8, and a left side is aperspective view showing an assembled state of the stacked mountingstructure separated into pieces in the right-side diagram;

FIG. 10 is a side view showing a structure of the stacked mountingstructure corresponding to steps from step S1 to step S6 in FIG. 8;

FIG. 11A is a perspective view showing a structure of a stacked mountingstructure according to a modified embodiment;

FIG. 11B is another perspective view showing the structure of thestacked mounting structure according to the modified embodiment;

FIG. 11C is still another perspective view showing the structure of thestacked mounting structure according to the modified embodiment;

FIG. 11D is another perspective view showing the structure of thestacked mounting structure according to the modified embodiment; and

FIG. 12 is a flow chart showing a flow of a method of manufacturingstacked mounting structure according to a modified embodiment.

EXPLANATION OF REFERENCE

-   -   10 stacked mounting structure    -   20 first substrate    -   20 a principal surface    -   21 electroconductive member    -   21 a end portion    -   22 electrode    -   23 insulating layer    -   23 a upper surface    -   24 circuit layer    -   26 electronic component    -   29 bump    -   30 second substrate    -   32 electrode    -   34 circuit layer    -   36 electronic component    -   40 stacked mounting structure    -   50 first substrate    -   51 electroconductive member    -   52 electrode    -   56 electronic component    -   57 reinforcing member    -   60 second substrate    -   66 electronic component    -   70 stacked mounting structure    -   80 first substrate    -   81 electroconductive member    -   83 insulating layer    -   88 wire    -   90 module

BEST MODE FOR CARRYING OUT THE INVENTION

Exemplary embodiments of a stacked mounting structure and a method ofmanufacturing stacked mounting structure according to the presentinvention will be described below in detail by referring to theaccompanying diagrams. However, the present invention is not restrictedto the embodiments described below.

In the method of manufacturing stacked mounting structure according tothe present invention, components to be mounted are mounted on a circuitboard and at the same time, from among these components to be mounted,an electroconductive member which is longer than a component having themaximum height is connected upon fixing in perpendicular with thesubstrate, to an electrode on the circuit board, and after filling aresin in a gap between the electroconductive member and the component tobe mounted, only a head portion of the electroconductive member isexposed by grinding. By connecting a second substrate to theelectroconductive member exposed, or, by forming a circuit by printingon a ground surface, the upper and the lower circuit boards areconnected and fixed electrically and mechanically, and accordingly, thestacked mounting structure according to the present invention is formed.Concrete embodiments will be described below.

First Embodiment

FIG. 1 is a perspective view showing a structure of a first embodimentof a stacked mounting structure according to the present invention, byseparating into a first substrate 20 and a second substrate 30.

As shown in FIG. 1, electronic components 26 are mounted on a principalsurface of the first substrate 20. Moreover, electronic components 36are mounted on the second substrate 30. The first substrate 20 and thesecond substrate 30 are disposed face-to-face. A multi-layer substrateor a substrate with built-in electronic components may be used for thefirst substrate 20 and the second substrate 30.

Electrodes 22 are provided between the electronic components 26 of thefirst substrate 20, and electroconductive members 21 having asubstantially circular cylindrical shape are installed on the electrodes22. A length of all the electroconductive members 21 is substantiallysame, and is longer than the maximum height of the electronic component26 from among the electronic components 26 mounted on the firstsubstrate 20. Moreover, an area of an orthogonal cross-sectionperpendicular to a longitudinal direction of the electroconductivemember 21 is same as or less than an area of the electrodes 22.

The electroconductive member 21 can be made easily by cutting out from awire, when a circular cylindrical shaped component is used. At thistime, when a diameter of an end portion of a side of theelectroconductive portion 21, to be mounted on the first substrate 20 ismade substantial, the mounting on the first substrate 20 can be carriedout easily and assuredly. Whereas, an end portion of theelectroconductive member, on the opposite side of the first substrate 20can also be mounted in a state of a number of electroconductive membersjoined.

For the electroconductive member 21, it is preferable to use a materialhaving a lower electrical resistance (such as Cu (copper)). Moreover, itis preferable to apply Au (gold) plating on a surface of theelectroconductive member 21 for preventing oxidation of a base material.Furthermore, a surface treatment for making soldering easy is carriedout on the electroconductive member 21, and one end portion of theelectroconductive member 21, and the electrode 22 are joined to beelectroconductive by soldering. Instead of soldering, it is possible tobring into electrical conduction by contact conduction by a method suchas an ACP method in which, an anisotropic conductive material is used,an ACF method, and an NCP method.

As shown in FIG. 2, circuit layers 24 and 34 are formed in the firstsubstrate 20 and the second substrate 30 respectively. An insulatinglayer 23 is formed by filling and curing an insulating material(reinforcing member) of a resin around the electroconductive member 21and the electronic components 26 on the first substrate 20. In theinsulating layer 23, only an end portion 21 a of the electroconductivemember 21, toward the second substrate 30 is exposed from a surface (anupper surface) 23 a toward the second substrate 30.

Electrodes 32 are installed on a surface 30 a of the second substrate30, facing the first substrate 20, at positions facing theelectroconductive members 21. The second substrate 30 is joined to asurface of the insulating surface 23 such that the end portions 21 a ofthe electroconductive members 21 of the first substrate 20 and theelectrodes 32 are connected electrically. The number of stacked layersmay be increased further by installing electroconductive members (notshown in the diagram) on electrodes (not shown in the diagram) on theexposed surface of the second substrate 30.

In the first embodiment, since the electroconductive member connectingthe upper and the lower circuit boards can be installed freely betweenthe electronic components, a wiring design of each substrate is notconstrained. Furthermore, the electrode on which the electroconductivemember is mounted not being a through hole electrode, a land electrodeis not necessary, and the electroconductive members can be disposed at anarrow pitch. Therefore, it is possible to provide a stacked mountingstructure having a small area of a principal surface of a substrate.Moreover, since processes such as cutting of through holes and recessesin the substrate are not necessary, it is possible to provide a stackedmounting structure at a low price and having a small area of theprincipal surface of the substrate.

Second Embodiment

FIG. 3 is a perspective view showing a structure of a second embodimentof a stacked mounting structure according to the present invention, byseparating into a first substrate 50 and a second substrate 60. FIG. 4is an enlarged perspective view showing a relationship of anelectroconductive member and a reinforcing member according to thesecond embodiment.

The second embodiment differs from the first embodiment at a point that,a reinforcing member 57 is formed in a state of a part or whole of amounting area exposed around an electroconductive member 51. In otherwords, the first substrate 20, the electrode 22, the electroniccomponent 26, the second substrate 30, the electronic component 36 inthe stacked mounting structure 10 of the first embodiment correspond tothe first substrate 50, the electroconductive member 51, an electrode52, an electronic component 56, the second substrate 60, and anelectronic component 66 respectively in a stacked mounting structure 40of the second embodiment. Moreover, although it is not shown in thediagram, even in the stacked mounting structure of the secondembodiment, a circuit layer similar to the circuit layers 24 and 34 ofthe stacked mounting structure 10 of the first embodiment is formed.

In the second embodiment, the electronic components being exposed afterforming the reinforcing member, the electronic components can be checkedimmediately before connecting the second substrate, and the number ofdefective stacked mounting structures can be reduced.

As shown in FIG. 4, the reinforcing member 57 is disposed such that anend portion 51 a toward the second substrate 60 is left around theelectroconductive member 51. As the reinforcing member 57, a materialwhich is in a liquid format the time of disposing around theelectroconductive member 51, and which is hardened after disposing is tobe used.

Third Embodiment

FIG. 5 is a perspective view showing a structure of a third embodimentof a stacked mounting structure according to the present invention.

In a stacked mounting structure 70 of the third embodiment, similarly asthe insulating layer 23 of the first embodiment, an insulating layer 83by an insulating material of a resin is formed around electroniccomponents (not shown in the diagram) and electroconductive members 81on a first substrate 80, and on a surface of the insulating layer 83,which is far from the first substrate 80, wires 88 are formed to connectthe electroconductive members 81. In other words, in the thirdembodiment, without placing a second substrate such as the secondsubstrate 30 of the first embodiment and the second substrate 60 of thesecond embodiment, the wires 88 are formed directly on the insulatinglayer 83. As a method for forming the wires 88, a method such asplating, sputtering, vapor deposition, and printed wiring by an ink-jetor dispensing may be used. By letting the structure to be suchstructure, since a substrate portion of the second substrate is notnecessary, it is possible to improve a degree of freedom of designing,and to provide a stacked mounting structure with a low stacking height,and small area of a principal surface of the substrate.

Modified Embodiments

Next, modified embodiments of the stacked mounting structure will bedescribed below. FIG. 11A, FIG. 118, FIG. 11C, and FIG. 11D showstructures of stacked mounting structures according to the modifiedembodiments.

As it has been mentioned above, the end portion of the electroconductivemember 21 toward the opposite side of the first substrate 20 can bemounted in the state of the number of electroconductive members 21joined. The state of the number of electroconductive members 21 joinedcan be formed by forming the electroconductive members 21 by plating ofCu on a substrate 100, or by carrying out press working on a plate 100of an electroconductive material such as Cu (FIG. 11A).

In this embodiment, an electroconductive member 21 which is connected isprepared separately from the first substrate 20, and is connected to thefirst substrate 20. FIG. 11B shows a state of a pin-substrate joining.Moreover, as shown in FIG. 11C, a resin is applied between a portionwhere the first substrate 20 and the electroconductive members 21 arejoined, and cured. Here, a resin may be applied in advance on the firstsubstrate 20.

The portion at which, the first substrate 20 and the electroconductivemembers 21 are joined is removed by grinding, and each electroconductivemember 21 is exposed. A metal film which prevents oxidation of theelectroconductive member 21 is formed at the end portion of the exposedelectroconductive members 21. Finally, the second substrate 30 isstacked as shown in FIG. 118, and the substrates 20 and 30 areconnected. Accordingly, the stacked mounting structure is formed.Therefore, in a case in which, the height of the electronic component 26is comparatively high such as from 0.3 mm to 1 mm, by disposing freelythe electroconductive members 21 longer than the height of theelectronic component 26 on a principal surface 20 a of the firstsubstrate 20, it is possible to connect the first substrate 20 and thesecond substrate 30. Moreover, it is possible to narrow a pitch ofconnections.

In such manner, the electroconductive members 21 are mountedcollectively on the first substrate 20 in the state of the plurality ofone end portions joined. Therefore, it is possible to mount theelectroconductive members 21 easily. Moreover, since protrudingelectrodes can be prepared collectively, further narrowing of pitch ispossible. As a result, the stacked mounting structure can be easilymanufactured to be small.

Next, a method of manufacturing stacked mounting structure according tothe present invention will be described below by citing embodiments froma fourth embodiment to a sixth embodiment

Fourth Embodiment

FIG. 6 is a flowchart showing a flow of a method of manufacturingstacked mounting structure according to the fourth embodiment. Themethod of manufacturing of the fourth embodiment is applicable toembodiments from the first embodiment to the third embodiment, and themodified embodiments, and in the description of the embodiments from thefourth embodiment to the sixth embodiment, reference numerals of thefirst embodiment are used.

Firstly, the electronic components 26 are mounted on the first substrate20 (step S1), and at the same time, the electroconductive members 21 aremounted on the electrodes 22 of the first substrate 20 (step S2). Formounting the electronic components 26, a prevalent surface mountingprocess may be used. Moreover, in a case of mounting theelectroconductive members 21 by soldering, the electroconductive members21 can be mounted by a method in which, a cream solder and flux aresupplied on the electrodes 22 by a method such as printing, and theelectroconductive members are positioned and fixed on the electrodes 22by using a mounting instrument and jig, and heated. For mounting theelectronic components 26 and the electroconductive members 21 on thefirst substrate 20, the electroconductive members 21 may be mountedafter the electronic components 26 are mounted (refer to the fifthembodiment or the sixth embodiment), or vice versa.

Next, the insulating layer 23 is formed around the electronic components26 and the electroconductive members 21 on the first substrate 20 byapplying a liquid sealing resin on the first substrate 20 on which theelectronic components 26 and the electroconductive members 21 aremounted such that, the end surface 21 a on the opposite side of thefirst substrate 20 (toward the second substrate 30) is exposed, and thencuring the liquid sealing resin. Accordingly, the electroconductivemembers 21 and the electronic components 26 are sealed (step S3). As acuring method of resin, methods such as a thermal curing and two-liquidmixing are available. The shape of the resin after curing can be seteasily by using a mould which is matched with an outer shape of thefirst substrate 20 or a desired shape after curing. In a case ofapplying the fourth embodiment to the second embodiment, at step S3,instead of sealing of a resin, a reinforcing member is to be disposedaround the electroconductive members.

Thereafter, the second substrate 30 is connected by stacking on thefirst substrate 20 via the bump in the form of a metal film formed on anend surface of the electroconductive member 21, on the opposite side ofthe first substrate 20. In a case of applying the fourth embodiment tothe third embodiment, without stacking the second substrate 30, wiresare formed directly on a surface 23 a of the insulating layer 23, on theopposite side of the first substrate 20.

The stacked mounting structure being manufactured by the abovementionedsteps, it is possible to provide the stacked mounting structure having asmall area of a principal surface of the substrate by extremely lessnumber of steps.

Fifth Embodiment

FIG. 7 is a flowchart showing a flow of a method of manufacturingstacked mounting structure according to a fifth embodiment. In the fifthembodiment, steps of mounting electronic components (step S1), mountingelectroconductive members (step S2), and resin sealing (step S3) beingsame as in the fourth embodiment, the description of these steps isomitted.

After the resin sealing (step S3), the upper surface 23 a of theinsulating layer 23 is ground and flattened to be parallel to theprincipal surface 20 a of the first substrate 20, as well as, each ofthe end surfaces 21 a of the electroconductive members 21, on theopposite side of the first substrate 20 is exposed (step S4).

Next, a metal film (UBM layer) is formed on the end surface 21 a of theexposed electroconductive member 21 (step S5). By forming the metallayer, it is possible to prevent oxidation of the electroconductivemember 21, and the electric resistance at the time of bump formation,which is the subsequent step, being low, it is possible to form a bumphaving a high strength.

Next, the bump is formed on the metal film which is formed on the endsurface 21 a of the exposed electroconductive member 21 (step S6).Solder or gold can be used as a material of bump.

Thereafter, the second substrate 30 is connected by stacking via a bump29 (FIG. 9 and FIG. 10) on the metal film which is formed on the endsurface 21 a of the electroconductive member 21.

By manufacturing the stacked mounting structure by such method, sincethe upper surface 23 a of the insulating layer 23 is flattened, andassuredly becomes parallel to the principal surface 20 a of the firstsubstrate 20, the end surface 21 a of the electroconductive member 21has a structure which makes it easy to connect the second substrate 30.Consequently, it is possible to provide a stacked mounting structurehaving a high quality of connection of the first substrate 20 and thesecond substrate 30, and small area of the principal surface of thesubstrate.

Sixth Embodiment

FIG. 8 is a flowchart showing a flow of a method of manufacturingstacked mounting structure according to a sixth embodiment. FIG. 9 is adiagram of which, a right side is an enlarged perspective view showing astructure of a stacked mounting structure corresponding to steps fromStep S1 to step S6 in FIG. 8, and left side is a perspective viewshowing an assembled state of the stacked mounting structure separatedinto pieces in the right-side diagram. FIG. 10 is a side view showing astructure of the stacked mounting structure corresponding to steps fromstep S1 to step S6 in FIG. 8.

In the sixth embodiment, steps of mounting electronic components (stepS1), mounting electroconductive members (step S2), resin sealing (stepS3), grinding (step S4), UBM layer formation (step S5), and bumpformation (step S6) are same as in the fifth embodiment. After formingthe bump 29, a plurality of modules 90 is formed on the first substrate20, and by a step of separating such as dicing, the modules are turnedto be individual modules (step S7).

According to such method of manufacturing, since it is possible toprepare a plurality of modules at a time, it is possible to provide astacked mounting structure in which, the cost of manufacturing modulesis low and the area of the principal surface of the substrate is small.

Modified Embodiments

FIG. 12 is a flow chart showing a flow of a method of manufacturingstacked mounting structure according to a modified embodiment. Samereference numerals are assigned to contents which are same as the stepsof the embodiments described above, and repeated description of suchsteps is omitted. To start with, in this modified embodiment, firstly,the electronic components 26 are mounted on the first substrate 20 (stepS1).

Cu is grown by plating on a substrate 100, at positions facingelectrodes provided between the electronic components 26 of the firstsubstrate 20. Accordingly, a state in which, one end portions of some ofthe electroconductive members 21 are connected is formed (step S2 a).

For the state in which, the one end portions of the electroconductivemembers 21 are connected, various methods such as forming Cu by platingon the substrate 10, furthermore, forming the electroconductive members21 by a method such as press working on a plate 100 of anelectroconductive material such as Cu, and plating the end surfaces in astate of the rod-shaped electroconductive members 21 arranged to bealigned on a jig, can be used. The electroconductive members 21 areformed such that the height of the electroconductive member 21 is morethan the height of the electronic component 26.

The end portion of the electroconductive member 21, on the side which isnot connected, is joined to the electrode of the principal surface 20 aof the first substrate 20 (step S2). In a state of the one end portionof the electroconductive member 21 joined, when Au plating is applied ona surface thereof, oxidation of Cu is prevented and the soldering can becarried out assuredly.

A resin is applied between portions at which, the first substrate 20 andthe electroconductive members 21 are joined, and cured (step S3). Here,the resin may be applied in advance on the first substrate 20.

A portion at which the first substrate 20 and the electroconductivemembers 21 are joined is removed by grinding, and each electroconductivemember 21 is exposed (step S4). Surrounding of the electroconductivemember 21 is reinforced by resin. Therefore, the electroconductivemember 21 can be ground stably. Furthermore, the height (length) of theelectroconductive members 21 can be arranged precisely by grinding.Therefore, a tolerance of length of the electroconductive member 21 tobe used can be widened.

When the height of the electronic components 26 is comparatively highsuch as from 0.3 mm to 1 mm, the electroconductive member 21 longer thanthe height of the electronic components 26 can be disposed freely on theprincipal surface 20 a of the first substrate 20, and the firstsubstrate 20 and the second substrate 30 can be joined. Moreover, pitchof connections can be narrowed.

Thereafter, a metal film which prevents oxidation of theelectroconductive member 21 is formed on the end portions of the exposedelectroconductive members 21. Next, by connecting the second substrate30, the stacked mounting structure is formed.

In such manner, the electroconductive members 21 are mounted on thefirst substrate 20 in the state of the plurality of one end portionsjoined. Therefore, the electroconductive members 21 can be mountedeasily. Moreover, since protruding electrodes can be preparedcollectively, further narrowing is possible. As a result, the stackedmounting structure can be easily manufactured to be small.

As it has been described above, according to the present invention,since the electroconductive members, which connect the upper and thelower circuit boards can be disposed freely between the electroniccomponents, wiring design of each substrate is not constrained.Furthermore, the electrodes on which, the electroconductive members aremounted not being through-hole electrode, land electrodes are notrequired, and the electroconductive members can be disposed with anarrow pitch. Therefore, it is possible to provide a stacked mountingstructure having a small area of the principal surface of the substrate.

INDUSTRIAL APPLICABILITY

In such manner, the stacked mounting stricture and the method ofmanufacturing stacked mounting structure according to the presentinvention are useful for small sizing of a mounting structure main body,and particularly, are appropriate for highly dense mounting of an imagepicking unit at a front end of an endoscope.

1. A stacked mounting structure comprising: a plurality of membersprovided with a mounting area, which is necessary for installing andoperating components to be mounted on at least one principal surface,and an area for connections for signal transfer for operating thecomponents to be mounted; and an electroconductive member which isdisposed on the area for connections between the mutually facingmembers, wherein a cross section of the electroconductive member is sameas or smaller than the area for connections, and an end portion of theelectroconductive member is extended from a principal surface of onemember up to a principal surface of the other member, and a height ofthe electroconductive member regulates a distance of the mounting area.2. The stacked mounting structure according to claim 1, wherein areinforcing member is installed around the electroconductive member. 3.The stacked mounting structure according to claim 1, wherein thecomponents to be mounted are mounted on the mounting area, and adistance of the mounting area between the plurality of members is morethan a height of the components to be mounted.
 4. The stacked mountingstructure according to claim 1, wherein the reinforcing member is filledin the mounting area between the mutually facing members.
 5. The stackedmounting structure according to claim 1, wherein the electroconductivemember is rod-shaped.
 6. The stacked mounting structure according toclaim 1, wherein the electroconductive member, in a state of one endportion thereof joined, the other end portion is mounted on the member,and is formed by removing the portion joined after the other end portionis mounted on the member.
 7. The stacked mounting structure according toclaim 1, wherein an electroconductive pattern of which, at least a partis electrically connected to the electroconductive member, is formed atone end portion of the reinforcing member.
 8. A method of manufacturingstacked mounting structure comprising steps of: mounting components tobe mounted, and mounting an electroconductive member which is higherthan a height of the components to be mounted, on a first member; areinforcing step of forming a reinforcing member around theelectroconductive member on the first member by exposing an end portionof the electroconductive member, at an opposite side of the firstmember, wherein at the reinforcing step, a surface of the reinforcingmember, opposite to the first member is flattened by grinding, and anend portion of the electroconductive member is exposed.
 9. The method ofmanufacturing stacked mounting structure according to claim 8,comprising: forming a metal film on an end-portion surface of theelectroconductive member which is exposed, after the reinforcing memberis formed by exposing the end portion of the electroconductive member,on the opposite side of the first member; and a step of forming a bumpon the metal film of the end-portion surface of the electro conductivemember.
 10. The method of manufacturing stacked mounting structureaccording to claim 8, further comprising: a joining step of forming oneend portion of the electroconductive member, in a state of the pluralityof electroconductive member joined.
 11. The method of manufacturingstacked mounting structure according to claim 8, comprising: aseparating step after an insulating-material forming step, wherein thefirst member has a size equivalent to a plurality of modules.